The invention relates to a disassemblable device for permitting the fitting of a device such as a valve between the opposite ends of two pipes.
It is known to use flanges, which are generally fixed by welding to each of the ends of the pipes for fitting a device such as a valve between two pipes.
The valve is then fitted by means of cords, i.e. ties which pass through aligned fixing holes formed in the flanges by moving together the flanges and the pipes. In view of the fact that before tightening the cords there can be a greater or lesser spacing between the flanges, the stress produced in the pipes and in their supports varies with said spacing and can reach very high levels when it exceeds a certain threshold. Moreover, when there is difficult access to the pipes, for example when they are disposed inside an enclosure or behind a wall the access opening made in this wall or in this enclosure can be displaced relative to the connecting device. This leads to difficulties in connection with the assembly and disassembly of the device and of the valve with which it is associated and these are made worse by the problems of access for valve control purposes. These difficulties become insurmountable when it is a question of a remote changing of a valve.
Another known dismantleable device has screwed couplings constituted by a nut or by a threaded end fitting mounted so as to rotate on the end of each of the pipes, said couplings being such that they are screwed to corresponding threaded end fittings formed on a device, such as a valve to be fitted between the opposite ends of the pipes. This device has disadvantages comparable to the device using cords. Thus, it also has the effect of moving the ends of the pipe towards one another. Moreover, this device is virtually unusable when the pipes are virtually inaccessible.
The two known devices described hereinbefore cannot be positioned in the immediate vicinity of a rigid wall, such as a concrete wall due to the space which must be provided in order to permit the assembly and disassembly of the device by means of a tool. Finally, the parallelism of the joining planes defined by the flanges must be obtained at the end of tightening, no matter what the shapes of the pipes and the complexity of the system formed by them.